High-Intensity Exercise Snacks for Reducing Mobile Phone Addiction in Adolescents (ES-MPA)

Effect of Fragmented Exercise Snacks on Mobile Phone Addiction and Psychophysical Health in Adolescents: A Randomized Controlled Trial

This study is a randomized controlled trial (RCT) designed to evaluate the long-term effectiveness of "Exercise Snacks" (fragmented, high-intensity bouts of exercise) in reducing mobile phone addiction among adolescents.

Participants will be randomly assigned to either an intervention group or a control group. The intervention spans 5 months and is followed by a 1-month follow-up period (Month 6). The intervention group will perform short bursts of exercise (e.g., 1-minute sprints, squats) multiple times daily during school breaks. The program is divided into three progressive phases: adaptation, enhancement, and consolidation. The study aims to determine whether this sustained "snack-style" exercise regimen can significantly lower mobile phone addiction scores, improve physical fitness, and enhance psychological traits such as self-control and resilience over a semester-long period.

Study Overview

• Status: Completed
• Conditions: Adolescent Behavior; Smartphone Addiction; Sedentary Behaviors
• Intervention / Treatment: Behavioral: Exercise Snacks Protocol

Detailed Description

Background and Rationale: Adolescents face increasing risks of mobile phone addiction, which is associated with sedentary behavior. "Exercise Snacks"-isolated bouts of vigorous exercise performed periodically throughout the day-offer a time-efficient solution. This study applies the COMB model and Self-Determination Theory to a long-term, semester-based intervention.

Study Design: This is a single-blind, randomized controlled trial conducted over a 6-month period (5 months of intervention + 1 month of follow-up).

Intervention Protocol: The intervention group follows a progressive "Exercise Snacks" program:

Adaptation Phase (Month 1 / Weeks 1-4): Focus on habit formation. Participants perform "Sprint Snacks" (e.g., stair climbing) 3 times daily and "Strength Snacks" (e.g., squats) 2 times weekly. Intensity is monitored to ensure safety and correct posture.

Enhancement Phase (Months 2-3 / Weeks 5-12): Focus on physiological adaptation. Frequency increases to 4 daily Sprint Snacks and 3 weekly Strength Snacks. A weekly collective High-Intensity Interval Training (HIIT) session is introduced to maximize cardiorespiratory benefits.

Consolidation Phase (Months 4-5 / Weeks 13-20): Focus on psychological integration. Daily snacks continue. Collective HIIT sessions increase to twice weekly. A cognitive-behavioral guidance component is added (bi-weekly) to help students identify phone use triggers and internalize healthy behaviors.

Follow-up Phase (Month 6 / Weeks 21-24): The structured intervention ceases. Participants are encouraged to maintain self-guided exercise. Final assessments are conducted at the end of Month 6 to evaluate the retention of intervention effects and any "rebound" in mobile phone addiction.

Outcome Measures: The primary outcome is Mobile Phone Addiction (SAS-SV), assessed at baseline, Month 3, Month 5 (post-intervention), and Month 6 (follow-up). Secondary outcomes include physical activity levels (PARS-3 and wearables), self-control (BSCS), resilience (RSCA), and mental health status.

• Study Type: Interventional
• Enrollment (Actual): 386
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Hong Kong
  • New Territories
    • Shatin, New Territories, Hong Kong
      • School of Physical Education, Jinan University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Adolescents aged 12-18 years enrolled in the participating middle/high school.
2. Owner of a smartphone with daily usage time > 2 hours.
3. Score on the Smartphone Addiction Scale-Short Version (SAS-SV) indicating a risk of addiction (e.g., score > 31 for males, > 33 for females).
4. Physically capable of participating in high-intensity exercise (PAR-Q screening negative).
5. Provided written informed consent (from both student and guardian).

Exclusion Criteria:

1. Diagnosed with severe physical disabilities or cardiovascular diseases that contraindicate high-intensity exercise (e.g., congenital heart disease).
2. Currently participating in other professional sports training or weight loss programs.
3. Diagnosed with severe psychiatric disorders (e.g., severe depression, schizophrenia) requiring medication.
4. Taking medications that affect heart rate or cognitive function.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Exercise Snacks Group; Participants in this group follow a 5-month structured "Exercise Snacks" protocol. The intervention consists of daily short bursts of high-intensity exercise (e.g., 1-minute sprints, squats) performed during school breaks, supplemented by weekly collective HIIT sessions. The program progresses through adaptation, enhancement, and consolidation phases.	Behavioral: Exercise Snacks Protocol; The intervention consists of a structured 5-month "Exercise Snacks" program. Participants perform "snacks"-defined as isolated bouts of vigorous-intensity physical activity (<2 min)-distributed 3-4 times throughout the school day during breaks. Content: The regimen includes "Sprint Snacks" (e.g., stair climbing, high knees) and "Strength Snacks" (e.g., squats, push-ups). Intensity: Participants are instructed to reach a subjective effort level of Borg RPE > 14 (Somewhat Hard to Hard). Progression: The program follows a phased approach: Adaptation (Month 1): Focus on habit formation and movement quality. Enhancement (Months 2-3): Increased frequency and inclusion of weekly collective HIIT sessions. Consolidation (Months 4-5): Integration of cognitive-behavioral guidance to replace mobile phone usage habits.; Other Names: Fragmented High-Intensity Exercise
No Intervention: Control Group; Participants in this group are instructed to maintain their usual daily campus life and academic routines without altering their existing physical activity habits. They do not participate in the structured exercise snacks program during the study period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Mobile Phone Addiction Severity (assessed by SAS-SV)	The severity of mobile phone addiction is measured using the Smartphone Addiction Scale-Short Version (SAS-SV). This self-report scale consists of 10 items. Each item is rated on a 6-point Likert scale ranging from 1 ("Strongly Disagree") to 6 ("Strongly Agree"). The total score is calculated by summing the scores of all 10 items, resulting in a range from 10 to 60. Higher scores indicate a higher level of mobile phone addiction risk.	Baseline, Month 3, Month 4, and Month 6

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objectively Measured Sleep Parameters via Wrist-Worn Accelerometer	Sleep parameters are continuously monitored using a consumer-grade wrist-worn accelerometer (Xiaomi Mi Band) for 7 consecutive days at each assessment time point. Primary sleep outcomes include total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE). Data are extracted from the device via the companion application and processed to derive nightly averages across the 7-day monitoring period. Participants are instructed to wear the device 24 hours per day, removing it only during water-based activities if the device is not waterproof.	Baseline, Month 3, Month 5, and Month 6
Psychological Resilience(CD-RISC-10 Score)	Psychological resilience is assessed using the Child and Youth Resilience Measure (CYRM). Higher scores indicate greater resilience.	Baseline, Month 2, Month 4, and Month 6
Self-Control Capacity (BSCS Score)	13 items, 1-5 scale. Range 13-65. Higher scores indicate better self-control.	Baseline, Month 2, Month 4, and Month 6.
Objectively Measured Daily Physical Activity via Wrist-Worn Accelerometer	Daily physical activity is continuously monitored using a consumer-grade wrist-worn accelerometer (Xiaomi Mi Band) for 7 consecutive days at each assessment time point. Outcomes include daily step count, duration of moderate-to-vigorous physical activity (MVPA), light physical activity, and sedentary time. Data are extracted from the device via the companion application and averaged across valid wear days (defined as ≥10 hours of wear time per day, with a minimum of 4 valid days required).	Baseline, Month 2,Month 4, and Month 6
Psychological Distress (DASS-21 Score)	Psychological distress is assessed using the Depression Anxiety Stress Scales-21 (DASS-21). The scale measures symptoms of depression, anxiety, and stress over the past week. Higher scores indicate greater psychological distress.	Baseline, Month 2, Month 4, and Month 6
Well-Being (WHO-5 Score)	Well-being is assessed using the WHO-5 Well-Being Index. Higher scores indicate better well-being.	Baseline, Month 2, Month 4, and Month 6
Basic Psychological Need Satisfaction (SDT Score)	Basic psychological need satisfaction is assessed using a self-determination theory-based scale. Higher scores indicate greater basic psychological need satisfaction.	Baseline, Month 2, Month 4, and Month 6
Emotion Regulation: Cognitive Reappraisal (ERQ Score)	Cognitive reappraisal is assessed using the Emotion Regulation Questionnaire (ERQ). Higher scores indicate greater use of cognitive reappraisal.	Baseline, Month 2, Month 4, and Month 6
Emotion Regulation: Expressive Suppression (ERQ Score)	Expressive suppression is assessed using the Emotion Regulation Questionnaire (ERQ). Higher scores indicate greater use of expressive suppression.	Baseline, Month 2, Month 4, and Month 6

Collaborators and Investigators

• Sponsor: Jinan University Guangzhou
• Investigators: Principal Investigator: Rui Si Ma, Jinan University

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2025
• Primary Completion (Actual): March 1, 2026
• Study Completion (Actual): March 1, 2026

Study Registration Dates

• First Submitted: January 3, 2026
• First Submitted That Met QC Criteria: January 3, 2026
• First Posted (Actual): January 13, 2026

Study Record Updates

• Last Update Posted (Actual): April 30, 2026
• Last Update Submitted That Met QC Criteria: April 25, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Digital Health; High-Intensity Interval Training; Self-Control; Exercise Snacks; Fragmented Exercise
• Additional Relevant MeSH Terms: Technology Addiction; Behavior, Addictive; Compulsive Behavior; Impulsive Behavior; Behavior; Social Behavior; Internet Addiction Disorder; Sedentary Behavior; Self-Control; Adolescent Behavior
• Other Study ID Numbers: SBRE-25-0472 (Other Identifier: Survey and Behavioural Research Ethics Committee of The Chinese University of Hong Kong)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data (IPD) that underlie the results reported in the article will be shared. This includes the text, tables, figures, and appendices. Data will be anonymized to protect participant privacy.
• IPD Sharing Time Frame: Beginning 3 months following article publication and ending 5 years following article publication.
• IPD Sharing Access Criteria: Data will be available to researchers who provide a methodologically sound proposal for meta-analysis or verification purposes. Proposals should be directed to the Principal Investigator at penny@link.cuhk.edu.hk. To gain access, data requestors will need to sign a data access agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ANALYTIC_CODE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No